Logo is here: [1 ]
A very simple programming language targeted at teaching children logical structure. It principal mechanism is the graphical "turtle" which can be moved with simple commands and can draw a line as it goes.
But the scope of the language is large enough with other areas like arithmetics and string handling. The concept of lists is central in Logo, so you might call it a scaled-down LISP with much much less parentheses... Long before RS knew Tcl, he liked Logo best for the simplicity of expressing algorithms - just for practical purposes it was not really fit on a Z80 8-bit box.
AM I have read the book "Introducing LOGO" by Boris Allan (Granada Technical Books, 1984, ISBN 0-246-12323-0) to get acquainted with the language and more importantly the ideas behind it. Several Wiki pages, among which A simple version of Eliza were inspired by this book. The aim: get some material together to teach programming to children